1. Field of the Invention
The present invention relates to a hydrogen burning turbine plant for burning hydrogen and oxygen to generate steam for thereby driving a turbine, and specifically to such a turbine plant in which a turbine operation at a starting time of the plant is facilitated, and a steam utilizing efficiency is enhanced.
2. Description of the Prior Art
A concept of a hydrogen burning turbine plant in which hydrogen and oxygen are burned in a combustion apparatus to generate steam of about 3,000.degree. C. for thereby driving a turbine is presently being studied, and systems thereof having various features are known now. But in the practical use thereof, there are various problems such that it is the present situation that an ensured technology has not yet been obtained. Examples of such a hydrogen burning turbine plant will be shown in FIGS. 5 and 6 with outlined description as herebelow.
In a system of FIG. 5, which is disclosed in the Japanese laid-open patent No. Hei 6(1994)-299805, a cycle of steam is constructed such that a low temperature steam from a compressor 52 becomes a high temperature steam at a hydrogen oxygen combustor 50, and enters a turbine 53 for driving it so that power is generated at a generator 54. Then the steam which has become a low temperature steam flows in a heat exchanger 55 and returns to the compressor 52. The low temperature steam which has come out of the turbine 53 drives a condensing turbine 63 for thereby driving a generator 64 for power generation, and is then condensed to water at a condenser 65. Also, another cycle of steam is constructed such that water fed by a pump 62 is heated at the heat exchanger 55 to become steam, and then enters an expansion turbine 56 for thereby driving a generator 57 for power generation. Then the steam which has become a low temperature steam is heated to a high temperature at a hydrogen oxygen combustor 58, enters a condensing turbine 59 for thereby driving a generator 60 for power generation, is then condensed to water at the condenser 61, and then flows to the heat exchanger 55 again via the pump 62. In the present system, exhaust heat is recovered downstream of the turbines, and two units of the hydrogen oxygen combustors are provided, to thereby aim at a higher efficiency.
FIG. 6 shows another example of system using a hydrogen oxygen combustor. In the figure, a cycle of steam is constructed such that steam fed through a low pressure compressor 100, an intercooler 101 and a high pressure compressor 102 enters a hydrogen oxygen combustor 104 through a first heat exchanger 103 at which the steam is heated to a high temperature to drive a first turbine 105 for thereby driving a generator 114 for power generation. The steam then flows in the first heat exchanger 103 and a second heat exchanger 106 for producing exhaust heat, and after flowing through a third heat exchanger 107, a potion of the steam drives a second turbine 109 for thereby driving a generator 115 for power generation, and another portion of the steam flows through a fourth heat exchanger 108 to enter the low pressure compressor 100 again.
The steam which has become a low pressure steam after flowing in the second turbine 109 is condensed to water at a condenser 111, is heated at a first feedwater heater 117 and a second feedwater heater 118, flows in the fourth and third heat exchangers 108, 107, respectively, via a pump 112, to be heated by the exhaust heat. The water is then further heated to a high temperature at the second heat exchanger 106 and drives a third turbine 110 for thereby driving a generator 116 for power generation. Then, the steam which has become a low temperature steam is partially used for cooling of the first turbine 105, and remaining steam is returned to an outlet side of the high pressure compressor 102 to flow into the first heat exchanger 103.
Numeral 119 designates the cooling steam for the first turbine 105. In the present system, in order to attain a high efficiency of the compressors without making the pressure ratio higher, the system is so constructed that the heat exchangers are provided between the upstream side of the hydrogen oxygen combustor 104 and the downstream side of the first turbine 105. Thus, the exhaust heat is made use of efficiency.
As mentioned in the prior art examples of FIGS. 5 and 6, with respect to the system having the combustion apparatus for burning hydrogen and oxygen to generate a high temperature steam for thereby driving a turbine, there are considered and studied systems having various features for making effective use of the high temperature heat generated for obtaining a high efficiency. In order to make practical use thereof however, because the steam generated by burning hydrogen and oxygen is of a high temperature of about 3,000.degree. C., it becomes necessary to obtain some measure by which the high temperature steam at a sting time of the plant is diluted and reduced to a temperature such that it is able to be introduced into the turbine. Of all the various systems considered at the present time, there is no established system for appropriate staring and running of such systems.
Also, unless the control system is appropriate for starting the operation and continuing the operation until the steam condition of pressure and temperature is established at each portion of the cycle, wet steam can enter into the compressor or turbine, whereby there arises a risk of breakage of the compressor or turbine. It is necessary, therefore, to obtain an established system for watching conditions at each portion of the plant and appropriately controlling flow of steam there. In the present sate hydrogen burning turbine plant, although systems having various features are disclosed, there is not yet established a sufficient control system for effecting operation of an actual plant.
Further, in a prior art hydrogen burning turbine plant shown in FIG. 7, while a portion of exhaust gas (steam) coming out of a third turbine 110 is used as a cooling steam for turbine blades etc. of a first turbine 105, in order to obtain a higher efficiency of this turbine plant, it becomes necessary to reduce the cooling steam of the first turbine 105 as much as possible or to employ a cooling system having a small reduction in gross thermal efficiency.